Carriage and ribbon mechanism for calculating machines



g- 1964 .R. 1.. SCHULTZ 3,145,651.

CARRIAGE AND RIBBON MECHANISM FOR CALCULATING MACHINES Filed Nov. 1. 1960 4 Sheets-Sheet 1 mmvm.

RALPH L. SCHULTZ BY ATTORNEYS FIGJO Aug. 25, 1964 R. L. SCHULTZ 3,145,551

CARRIAGE AND RIBBON MECHANISM FOR CALCULATING MACHINES Filed Nov. 1. 1960 4 Sheets-Sheet 2 INVENTOR. .RALPH L. scuuuz;

ATTORNEYS.

Aug. 25, 1964 R. SCHULTZ 3,145,651

CARRIAGE AND RIBBON MECHANISM FOR CALCULATING MACHINES Filed NOV. l, 1960 4 Sheets-Sheet 3 20 I74 l\/\ 4 83 1 78 82 z 7o 7 I I80 J SLOT 80 n I I82 gal 76 r I we 64 we s s2 I I as ;@L will ee 60 I Q {1 x 72 as L 74 lss INVENTOR.

RALPH L. SCHULTZ BY w /M: a

ATTORNEYS g- 1964. R. L. SCHULTZ CARRIAGE AND RIBBON MECHANISM FOR CALCULATING MACHINES Filed NOV. '1. 1960 4 Sheets-Sheet 4 I I I I I i i I i I a: 1 f I i INVENTOR.

RALPH L. SCHULTZ ATTORNEYS ment of the position of the record tape.

United States Patent 3,145,651 CARRIAGE AND RIBBON MECHANISM FOR CALCULATING MAHINES Ralph L. Schultz, Chicago, Ill., assignor to Victor Comptometer Corporation, a corporation of Illinois Filed Nov. 1, 1960, Ser. No. 66,635 9 Claims. (Cl. 101-336) The invention relates generally to carriage and ribbon feed operating mechanisms for calculating machines, and more particularly to an improved means for ribbon reversal.

It is a principal object of the invention to provide an improved means and mechanism for causing reversal of the ribbon feed as the ribbon approaches a fully unwound condition on either of the spools.

A further object is to provide an improved ribbon supporting and actuating means in which a change of ribbon may be effected very easily and rapidly.

Other objects and advantages will appear from the following description, reference being had to the accompanying drawings, in which- FIG. 1 is a top view of the ribbon feeding mechanism, showing its relation to the platen and printing type;

FIG. 2 is a generally left side elevational view of the printing and platen operating mechanism of the machine, portions thereof being shown in section;

FIGv 3 is a side elevational view of the drive mechanism for effecting ribbon feed, the parts being shown in normal position;

FIG. 4 is a view similar to FIG. 3, showing the parts in position for printing the items or totals in red;

FIG. 5 is a view similar to FIG. 3, showing the parts in printing position;

FIG. 6 is a fragmentary sectional View, taken generally on the line 6 of FIG. 1;

FIG. 7 is a sectional view, taken on the line 77 of FIG. 6;

FIG. 8 is a fragmentary sectional view, taken on the line 8-8 of FIG. 7, the figure being rotated 90 counterclockwise;

FIG. 9 is a fragmentary end elevational view, taken on the line 9-9 of FIG. 7, this figure likewise being rotated 90 counterclockwise;

FIG. 10 isa view taken on the line Ill-10 of FIG. 4;

FIG. 11 is a sectional view showing a complete length of ribbon wound on the left-hand spool and completely unwound from the right-hand spool; and

FIG. 12 is a fragmentary sectional view, taken on the line 12-12 of FIG. 1.

The present invention is particularly adapted for use on adding and calculating machines having a platen operating mechanism for pressing the platen against the type, generally of the kind disclosed in Lippert Patent No. 2,318,000.

i The general organization of the mechanism for control- ,ling ribbon feed and reversingfand also for controlling the a red and black printing mechanism, is disclosed in FIG. 1 as comprising a deck 2% providing a support for ribbon spools 21 and 22, a ribbonfeed reversing mechanism 24, and the power means including a generally channel-shaped slide 26 (FIG. 10).

A platen 28 (FIGS. 1, 2, and 4) is rotatably mounted in a pair of carriage frame plates 30, 31, the platen shaft 32 being rotated to advance and retract the paper tape in the manner shown in the aforesaid patent, through pawl and ratchet means in the customary 'manner, or manually by a twirler knob 34. The twirler knob is suitably non rotatably secured to a shaft 36, and through pinion 38 (FIG. 12) direction reversing idler gear 40, and pinion 42 mountedon the platen shaft 32, permits manual adjust- "ice ' The power for swinging the platen 28 against the differentially positioned type of the type carriers 44 is derived from the rockable main shaft 46 (FIGS. 2, 3, 4, and 5) which has a plate 48 secured thereto, the plate having a sidewardly extending stud 50 normally engaging a notch 52 in an actuating link 54. In the usual construction, the plate 48, stud 50, notch 52, and link 54 are dupllicated for the right-hand side of the machine, but this mechanism for the left-hand side only of the machine will be described in detail. The link 54 is movable rearwardly upon the forward stroke (clockwise movement of rock shaft 46) of the machine, from the position shown in FIG. 2 to the position shown in FIG. 4, being guided by a stud 56 extending through slot 58 formed in the link 54. For purposes of adjustment the stud 56 may be eccentric.

The rearward end of the link 54, through the forward end of its slot 58, engages the stud 56 which is attached to the carriage frame plate 30, and operates to swing the platen 28 toward the type carriers 44 to effect a printing impression, as shown in FIG. 4.

The power for feeding the ribbon is derived from the main shaft 46 through a crank 60 fixed thereto and having a stud 62 cooperable with an inverted generally Y- shaped notch 64 formed at the forward end of a crank 66 which is biased to swing counterclockwise by a spring 68. It will be noted that the notch 64 is provided with initial and terminating surfaces which are elfectively concentric with the shaft 46 and thus provide that the crank 66 shall not be operated during the initial, nor during the final, portions of the forward (clockwise, FIG. 3) stroke of the main shaft 46, but that when the stud 62 engages in the central portion of the notch 64, the crank 66 is swung counterclockwise (FIG. 3) about its pivot 70, to the position shown in FIG. 5.

The forward end of a link 72 is pivotally connected to the arm 66, and its rearward end is connected to a bell crank 74, so that, during the forward stroke of the main shaft 46, the bell crank 74 is pivoted counterclockwise to the position shown in FIG. 5. The rearward arm of the bell crank 74 has pivoted thereto a link 76 which in turn is pivotally connected by a stud 78 to a pivot stud 80, the latter having end bearings in similar bell cranks $2 and 83 pivoted 'on a stud 84 mounted on a bracket 86, the latter being suitably secured to the left-hand frame plate 88 of the machine. The link 76, studs 78 and 80, thus form a universal joint.

As best shown in FIG. 10, the crank 82 and 83 carry a stud 90 having ta roller 92 projecting through a slot 34 in an offset arm 95 forming part of the power slide 26. This slide is suitably mounted for transverse reciprocatory motion on a pair of studs 98 extending through suitable elongated slots 18%) (FIG. 10) and by an additional central stud 102 (FIG. 1) projecting through a slot. 164.

As best shown in FIGS. 1 and 7, the power slide 26 has a pair of pawls 1G6, 107 pivotally secured thereto at 108, 109, respectively, these pawls having sidewardly bent lugs 110 engageable with ratchet Wheels 112, 113. 60

Depending upon the position of a ribbon feed reversing slide 114, one or the'other of the pawls lihi, 107 will be in position for engagement with its associated ratchet wheel 112, 113. The ratchet wheels 112,113, and the ribbon spools'21, 22 are ,inountedon studs 116, the spools being nonrotatably connected to the ratchet wheels by pins 111 on the ratchet wheelsand mating recesses 115 in the spools, but easily removable for replacement of the ribbon. The ratchet wheels 112, 113 have enlarged hubs 117 (right, FIG. 1)v which are engaged'by a pair of scissor arms 144 conformedto engage the hub 117 of the ratchet wheel 113, being; drawn together by a spring 146,, the inner ends of these arms pivotally engaging a pair of studs 148. The spring 146 applies sufiicient force to the arms 144 frictionally to hold the ratchet wheel in the position to which it is rotated by its pawl 107. The ratchet wheel 112 for the left-hand ribbon spool is similarly held frictionally in the position to which it has been moved.

The inked ribbon 118 is wound up on one spool or the other in the customary manner, and the direction of feed of the ribbon is determined by the ribbon reversing mechanism 24 (FIG. 11). The ribbon 118 is guided by pins 120 (FIGS. 7 and 11) to lie between the platen 28 and the type carriers 44. When the spool 21 has substantially all of the ribbon wound thereon, a pin 122 carried by a lever 124, pivoted on a stud 126, is in the position shown in FIG. 11.

While the ribbon reversing mechanism is herein particularly shown and described with reference to the righthand ribbon spool 22, it will be understood that a complementary mechanism, operating in a similar manner, is provided for the left-hand spool 21.

The right-hand lever 124 is urged to swing counterclockwise (the left-hand crank 124 clockwise, FIGS. 7 and 11) by a tension coil spring 127 anchored to the lever 124 as well as to the deck 24}, thus keeping pin 122 in contact with ribbon 118 when a small number of turns of ribbon is left on hub 135 of ribbon spool 22. (This description will continue by referring only to the right-hand spool, it being understood that the construction and operation of the left-hand spool mechanism is reciprocal.) The bell crank 130, having a sidewardly extending lug 132, is also pivoted on stud urged by a tension coil spring 123 against a stud 129 eccentrically mounted on lever 124. The eccentric stud 129 permits adjustment of the movement of lug 132 for effective engagement with a shoulder 134 of reversing slide 114 during the ribbon feed reversing operation.

From FIG. 11 it will be quite apparent that when the ribbon spool 21 has a large number of turns of ribbon 118, the direction in which the ribbon passes from the spool 21 to the pin 120 is at a substantially greater angle than when the ribbon has substantially unwound from hub 135 of the ribbon spool 22. This change of direction of the movement of the ribbon web results in swinging the arm 124 clockwise to the position shown on the right ribbon spool 22 of FIG. 11, thereby biasing the bell crank 130 to swing clockwise to cause its lug 132 to move into position for engagement with shoulder 134 of the reversing slide 114 during the return stroke of the power slide 26.

As shown on the right side in FIG. 11, the heel adjacent to the shoulder 134 of the reversing slide 114 constrains the lug 132 of hell crank 130 from a clockwise motion. However, the ribbon 118 has swung arm 124 clockwise, thereby stretching the spring 123 and dis engaging the crank 130 from contact with the eccentric stud 129. As soon as the reversing slide 114 moves to the left, carried by the power slide 26 during the following machine cycle, the spring 128 pulls crank 130 clockwise against stud 129 so that lug 132 moves into the path of shoulder 134 of the reversing slide 114.

Toward the end of the return stroke of the power and reversing slides, the lug 132 engaging the shoulder 134 prevents the reversing slide 114 to return to its right- 7 most position (FIGS. 7 and 11) and assumes a position whereby stud 138 is lodged in notch 141) at the left side of reversing slide 114.

vAs-shown in FIG. 7, the left-hand feed pawl 196 has 26 and is a sidewardly extending stud 138, while the right-hand" feed pawl 107 has a similar stud 139. As shown in FIG. 11, the feed reversing slide 114 is provided with a notch 140 (at each end thereof) for the reception of the studs 138 and 139, thus serving as detents to hold the reversing slide 114 in the position to which it'has been shifted, and in addition, to permit a tension spring 142 (FIG. 7) to lower the particular pawl 106 or 107 toa position such that it may engage its associated ratchet wheel 112, 113. In FIG. 7, the left-hand ribbon feed pawl is shown in position to have its lug or tooth 110 in position for eifective engagement with the ratchet wheel 112, while the spring 142 at the right is extended by virtue of the engagement of its stud 139 in the notch of the reversing slide 114.

After the reversing slide 114 is shifted to the left, stud 138 of feed pawl 106 is lodged in notch 140 at the left of slide 114. This shifting causes the inclined surface 141 of slide 114 to move stud 138 of pawl 1116 clockwise into the adjacent notch 140, thus camming lug 110 of the pawl 106 out of engagement with ratchet wheel 112, while stud 139 of pawl 107 (at the right side of FIGS. 7 and 11) leaves its notch 140, and lug 110 of pawl 107 is forced into engagement with its associated ratchet wheel 113 by the pull of spring 142. During the ensuing machine operations, the pawl 1197 actuated by the reciprocatory motion of the power slide 26 will, through its lug 110, cause the ratchet wheel 113 to rotate counterclockwise, thus rewinding the right-hand spool 22 with the ribbon web 118 and unwinding the left-hand spool 21.

In review, it may be emphasized that, as shown in FIG. 7, the left-hand feed pawl 1136 has a sidewardly extending stud 138, while the right-hand feed pawl 1117 has a similar stud 139. As shown in FIG. 11, the feed reversing slide 114 is provided with a notch 141) (at each end thereof) for the reception of the studs 13% and 139, which thus serve as detents to hold the reversing slide 114 in the position to which it has been shifted, and in addition, to permit a tension spring 142 to lower the particular pawl 196 or MP7 to a position such that it may engage its associated ratchet wheel 112, 113. In FIG. 7, the lefthand ribbon feed pawl is shown in position to have its lug or tooth 110 in position for effective engagement with the ratchet wheel 112, while the spring 142 is extended by virtue of the engagement of its stud 139 with the raised edge of the reversing slide 114.

In order to secure printing of items subtracted and negative totals in a distinctive color, the customary two color ribbon is employed, the lower portion being colored red and the upper portion black. It is therefore necessary, upon such negative indications, to move the ribbon deck upwardly.

Upon each subtract operation or negative total operation, a slide 1 61) is moved downwardly (FIG. 2), this slide being suitably mounted for generally vertical sli ing motion on a pair of studs 162-, 163, extending through suitably elongated slots 164. The manner in which this slide is operated is fully disclosed in the prior patent to Thomas O. Mehan, No. 2,550,581, being shown as part 222 in FIG. 4 thereof. The slide shown in said patent is modified by the addition of a stud 1%. Upon downward movement of the slide 160, the stud 166 engages the rearwardly extending arm of a bail-form bell crank lever 168, swinging the latter counterclockwise. Upon such movement, the rearwardly extending arm 119 of the crank 168 moves a stud 170 upwardly through a clearance slot 172, to the position shown in FIG- 4, and thus permits counterclockwise pivotal movement of a lever 174 (FIG. 5) about its pivot stud 176 mounted on a bell crank 178, causing a sidewardly extending lug 181 on its rearwardly extending arm to swing to a position in which it may be engaged by a projection 182 on a power driving arm 184. The arm 184 is pivoted on a stud 186 and is con- ,nected by a link 1&8 with the bell crank lever 74 which,

as previously described, is oscillated during each cycle of operation of the machine.

The positioning of the lug in front of the projection 182 results in forming a positive driving connection for swinging the ribbon deck 20 counterclockwise (FIG. 5)

about'the pivot shaft 36 a sufiicient distance to'bring the 7 lower red portion of the ribbon in registry with the printing line, as shown in FIG. 4. By reference to the afore said Patent No. 2,550,581, it will'be clear that such shifting of the ribbon deck will take place upon initiation of each subtraction cycle and upon each negative total taking cycle. A bias spring 190 urges the ribbon deck toward its home position.

While there has been described What is believed to be the preferred embodiment of the present invention, it will be appreciated that various changes and modifications may be made therein; and it is contemplated to cover in the appended claims all such changes and modifications as fall Within the true spirit and scope of the invention.

What is claimed as new and desired to be secured by United States Letters Patent is:

1. In a calculating machine having a pair of spaced spools carrying a ribbon adapted to be fed alternately for winding on one spool and then the other, a ribbon feeding and reversing mechanism comprising a deck hav ing means rotatably supporting the spools, a pair of ratchet wheels each connected for rotation with a respective spool, a power slide mounted on the deck for reciprocable movemen in the direction of one spool and then the other, a reversing slide mounted on the power slide for limited reciprocable movement relative thereto and having a pair of spaced notches, a pair of pawls pivotally carried by the power slide each having a lug engageable with a respective ratchet wheel and each having a stud engageable with a respective notch in the reversing slide, a pair of springs each secured to the power slide and to a respective pawl urging the pawls toward normal positions for stepping engagement with the ratchet wheels upon reciprocable movement of the power slide, and cam surfaces on the reversing slide cooperating with the springs to urge one or the other pawl from its normal position into an inoperative non-stepping position for engagement of its stud in the respective notch latching the reversing slide to the power slide to cause reciprocable movement of the reversing slide with the power slide and to urge the opposite pawl into its normal position so that on reciprocation of the power slide only one pawl steppingly engages its respective ratchet wheel to feed the ribbon.

2. In a calculating machine having a pair of spaced spools carrying a ribbon adapted to be fed alternately for winding on one spool and then the other'and having a main shaft operated in timed relation with the operation of the machine, aribbon feeding and reversing mechanism comprising a deck having means rotatably supporting the spools, a pair of ratchet wheels each connected for rotation with a respective spool, a power slide mounted on the deck for reciprocable movement in the direction of one spool and then the other, a reversing slide mounted on the power slide for limited reciprocable movement relative thereto and having a pair of spaced notches, a pair of pawls pivotally carried by the power slide each having a lug engageable with a respective ratchet wheel and each having a stud engageable with a respective notch in the reversing slide, a pair of springs each secured to the power slide and to a respective pawl urging the pawls toward normal positions for stepping engagement with the ratchet wheels upon reciprocable movement of the power slide, cam surfaces on the reversin slide cooperating with the springs to urge one or the other pawl from its normal position intoan inoperative nonstepping position for engagement of its stud in the respective notch latching the reversing slide to the power slide to cause reciprocable movement of the reversing slide with the power slide and to urge the oppo site pawl into its normal position so that on reciprocation of the power slide only one pawl steppingly engages its respective ratchet wheel to feed the ribbon, and means connecting the power slide to the main shaft for movement of a ratchet wheel one step by the said normally positioned pawl during each cycle of machine operation.

3. In a calculating machine havin a pair of spaced spools carrying a ribbon adapted to be fed alternately for winding on one spool and then the other and having a main shaft rocked in timed relation with the operation of the machine, a ribbon feeding and reversing mechanism comprising a deck having means rotatably supporting the spools, a pair of ratchet wheels each connected for rotation with a respective spool, a power slide mounted on the deck for reciprocable movement in the direction of one spool and then the other, a reversing slide mounted on the power slide for limited reciprocable movement relative thereto and having a pair of spaced notches, a pair of pawls pivotally carried by the power slide each having a lug engageable with a respective ratchet wheel and each having a stud engageable with a respective notch in the reversing slide, a pair of springs each secured to the power slide and to a respective'pawl urging the pawls toward normal positions for stepping engagement with the ratchet wheels upon reciprocable movement of the power slide, cam surfaces on the reversing slide cooperating with the springs to urge one or the other pawl from its normal position into an inoperative I non-stepping position for engagement of its stud in the respective notch latching the reversing slide to the power slide to cause reciprocable movement of the reversing slide with the power slide and to urge the opposite pawl into its normal position so that on reciprocation of the power slide only one pawl steppingly engages its respective ratchet wheel to feed the ribbon, a first crank secured to the main shaft and having a stud thereon, a pivotal second crank having a lost motion connection with the stud for pivotal movement of the second crank only during the intermediate portion of each pivotal movement of the first crank, and linkage connecting the second crank to the power slide for reciprocally shifting the latter in timed relation with the operation of the machine.

4. The combination of claim 3 in whichthe lost mo- 7 tion connection comprises a stud carried by the first crank and a notch at one end of the second crank receiving the crank stud, the notch having a first curved surface concentric With the axis of the first crank in the home position of the second crank, having a second curved surface concentric with said axis in an actuated position of the second crank and having a central recessed portion extending away from the first crank.

5. In a calculating machine having a pair of spaced spools carrying a ribbon adapted to be fed alternately I for Winding on one spool and then the other, a ribbon feeding and reversing mechanism comprising a deck having means rotatably supporting the spools, a pair of ratchet wheels each connected for rotation with a respective spool, a power slide mounted on the deck for reciprocable movement in the direction of one spool then the other, a reversing slide mounted on the power slide for limited reciprocable movement relative thereto and having a pair of spaced notches, a pair of pawls pivotally carried by the power slide each having 2. lug engageable with a respective ratchet wheel and each having a stud engageable with a respective notch, a pair of springs each secured to the power slide and to a respective pawl urging the pawls toward normal positions for stepping engagement with the ratchet wheels upon reciprocable movement of the power slide, cam surfaces on the reversing slide cooperating with the springs to urge one or the other pawl from its normal position into an inoperative non-stepping position for engagement of its stud in the respective notch to cause reciprocable movement of the reversing slide with the power slide and to urge, the opposite pawl into its normal position, and a pair of linkages each responsive to substantial exhaustion of ribbon from a respective spool engaging the reversing slide during movement of the power slide to shift the reversing slide relative to the power slide urging one of the pawls from its inoperative position to its normal position and the other pawl from its normal position to its inoperative position, thereby to reverse the direction of ribbon feed.

6. The combination set forth in claim 5 in which each linkage comprises a first pivoted link having a stud engageable with the ribbon adjacent its respective spool, a spring connected to the link urging the latter stud toward the ribbon, a second pivoted link having a lug engageable for winding on one spool and then the other, a ribbon feeding and reversing mechanism comprising a deck having means rotatably supporting the spools, a pair of ratchet wheels each connected for rotation with a respective spool, a power slide mounted on the deck for reciprocable movement in the direction of one spool and then the other, a reversing slide mounted on the power slide for limited reciprocable movement relative thereto, means movably carried by the power slide and engageable with the reversing slide for holding the reversing slide alternatively in one of two extreme positions on the power slide, said last named means being positioned by the reversing slide depending upon its position on the power slide for alternative stepping engagement with one of the two ratchet wheels upon reciprocable movement of the power slide, and a pair of linkages each responsive to substantial exhaustion of ribbon from a respective spool engaging the reversing slide during movement of the power slide to shift the reversing slide relative to the power slide thereby positioning the latter means for reversal of the direction of ribbon feed.

8. In a calculating machine having a pair of spaced spools carrying a ribbon adapted to be fed alternately for winding on one spool and then the other and having a main shaft operated in timed relation with the operation of the machine, a ribbon feeding and reversing mechanism comprising a deck having means rotatably supporting the spools, a pair of ratchet wheels each connected for rotation with a respective spool, a power slide mounted on the deck for reciprocable movement in the direction of one spool and then the other, a reversing slide mounted on the power slide for limited reciprocable movement relative thereto and having a pair of spaced notches, a pair of pawls pivotally carried by the power slide each having a lug engageable with a respective ratchet wheel and each having a stud engageable with a respective notch in the reversing slide, a pair of springs each secured to the power slide and to a respective pawl urging the pawls toward normal positions for stepping engagement with the ratchet wheels upon reciprocable movement of the power slide, cam surfaces on the reversing slide cooperating with the springs to urge one or the other pawl from its normal position into an inoperative position for engagement of its stud in the respective notch latching the reversing slide to the power slide to cause reciprocable movement of the reversing slide with the power slide and to urge the opposite pawl into its normal position so that on reciprocation of the power slide only one pawl steppingly engages its respective ratchet wheel to feed the ribbon, a pair of linkages each responsive to substantial exhaustion of ribbon from a respective spool engaging the reversing slide during movement of the power slide to shift the reversing slide relative to the power slide urging one of the pawls from its inoperative position to its normal position and the other pawl from its normal position to its inoperative position thereby to reverse the direction of ribbon feed, and means connecting the power slide to the main shaft for movement during each cycle of machine operation of a ratchet wheel one step by the pawl which is in its normal position.

9. In a calculating machine having a deck for supporting a pair of ribbon spools in spaced relation, a spool mounting assembly comprising a stud carried by the deck, a ratchet wheel having a hub rotatably mounting the wheel on the stud in spaced relation to the deck, a spool rotatably mounted on the stud adjacent its outer end, cooperating pin and recess means on the wheel and spool preventing relative rotation therebetween, means retaining the wheel against axial movement on the stud, a pair of studs carried by the deck adjacent the hub, a pair of scissor arms on either side of the hub each having an end received between the latter studs and having curved surfaces complemental with and engaging a respective stud and a portion of the hub, and a spring connected to the opposite ends of the scissor arms urging the arms into pivotal engagement with respective studs and into frictional engagement with the hub.

References Cited in the file of this patent UNITED STATES PATENTS 1,643,266 Aichele Sept. 20, 1927 1,788,376 Barrett Jan. 13, 1931 1,950,725 Garbell d. Mar. 13, 1934 2,011,310 Anderson Aug. 13, 1935 2,267,885 Anderson Dec. 30, 1941 2,725,969 Duke Dec. 6, 1955 2,734,455 Phinney Feb. 14, 1956 2,821,918 Llorens Feb. 4, 1958 2,906,203 Grosse Sept. 29, 1959 2,919,641 Pfleger Jan. 5,1960 2,951,439 Stutz et a1 a- Sept. 6, 1960 

1. IN A CALCULATING MACHINE HAVING A PAIR OF SPACED SPOOLS CARRYING A RIBBON ADAPTED TO BE FED ALTERNATELY FOR WINDING ON ONE SPOOL AND THEN THE OTHER, A RIBBON FEEDING AND REVERSING MECHANISM COMPRISING A DECK HAVING MEANS ROTATABLY SUPPORTING THE SPOOLS, A PAIR OF RATCHET WHEELS EACH CONNECTED FOR ROTATION WITH A RESPECTIVE SPOOL, A POWER SLIDE MOUNTED ON THE DECK FOR RECIPROCABLE MOVEMENT IN THE DIRECTION OF ONE SPOOL AND THEN THE OTHER, A REVERSING SLIDE MOUNTED ON THE POWER SLIDE FOR LIMITED RECIPROCABLE MOVEMENT RELATIVE THERETO AND HAVING A PAIR OF SPACED NOTCHES, A PAIR OF PAWLS PIVOTALLY CARRIED BY THE POWER SLIDE EACH HAVING A LUG ENGAGEABLE WITH A RESPECTIVE RATCHET WHEEL AND EACH HAVING A STUD ENGAGEABLE WITH A RESPECTIVE NOTCH IN THE REVERSING SLIDE, A PAIR OF SPRINGS EACH SECURED TO THE POWER SLIDE AND TO A RESPECTIVE PAWL URGING THE PAWLS TOWARD NORMAL POSITIONS FOR STEPPING ENGAGEMENT WITH THE RATCHET WHEELS UPON RECIPROCABLE MOVEMENT OF THE POWER SLIDE, AND CAM SURFACES ON THE REVERSING SLIDE COOPERATING WITH THE SPRINGS TO URGE ONE OR THE OTHER PAWL FROM ITS NORMAL POSITION INTO AN INOPERATIVE NON-STEPPING POSITION FOR ENGAGEMENT OF ITS STUD IN THE RESPECTIVE NOTCH LATCHING THE REVERSING SLIDE TO THE POWER SLIDE TO CAUSE RECIPROCABLE MOVEMENT OF THE REVERSING SLIDE WITH THE POWER SLIDE AND TO URGE THE OPPOSITE PAWL INTO ITS NORMAL POSITION SO THAT ON RECIPROCATION OF THE POWER SLIDE ONLY ONE PAWL STEPPINGLY ENGAGES ITS RESPECTIVE RATCHET WHEEL TO FEED THE RIBBON. 